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Polyphenol polymerization by horseradish peroxidase for metal adsorption studies / Hidetaka Kawakita in Industrial & engineering chemistry research, Vol. 48 N° 9 (Mai 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 9 (Mai 2009) . - pp. 4440–4444 Titre : Polyphenol polymerization by horseradish peroxidase for metal adsorption studies Type de document : texte imprimé Auteurs : Hidetaka Kawakita, Auteur ; Kohshi Hamamoto, Auteur ; Keisuke Ohto, Auteur Année de publication : 2009 Article en page(s) : pp. 4440–4444 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Polyphenol  Horseradish  peroxidase  reaction  Fourier  transform  infrared  spectrometry  Size-exclusion  chromatography  Metal  adsorption Résumé : Four phenol derivatives (m-cresol, 3-methylcatechol, 4-methylcatechol, and 4-ethylcatechol) were polymerized using the horseradish peroxidase reaction, and their metal adsorption capabilities were studied. Fourier transform infrared (FT-IR) spectrometry and size-exclusion chromatography indicated that the phenol monomers polymerized to give polyphenols having molecular weights from 700 to 3000. During metal adsorption studies, poly(3-methylcatechol) adsorbed copper ions at 100% in a solution of pH 5.0, whereas poly(m-cresol) failed to adsorb any copper ions. Gold ions selectively adsorbed to poly(4-ethylcatechol) in acid media and formed gold particles via reduction of the polyphenol. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800830m [article] Polyphenol polymerization by horseradish peroxidase for metal adsorption studies [texte imprimé] / Hidetaka Kawakita, Auteur ; Kohshi Hamamoto, Auteur ; Keisuke Ohto, Auteur . - 2009 . - pp. 4440–4444. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 9 (Mai 2009) . - pp. 4440–4444 Mots-clés : Polyphenol  Horseradish  peroxidase  reaction  Fourier  transform  infrared  spectrometry  Size-exclusion  chromatography  Metal  adsorption Résumé : Four phenol derivatives (m-cresol, 3-methylcatechol, 4-methylcatechol, and 4-ethylcatechol) were polymerized using the horseradish peroxidase reaction, and their metal adsorption capabilities were studied. Fourier transform infrared (FT-IR) spectrometry and size-exclusion chromatography indicated that the phenol monomers polymerized to give polyphenols having molecular weights from 700 to 3000. During metal adsorption studies, poly(3-methylcatechol) adsorbed copper ions at 100% in a solution of pH 5.0, whereas poly(m-cresol) failed to adsorb any copper ions. Gold ions selectively adsorbed to poly(4-ethylcatechol) in acid media and formed gold particles via reduction of the polyphenol. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800830m

Reduction of gold ions to gold particles by reusable soluble poly (tyramine) polymerized by horseradish peroxidase / Hidetaka Kawakita in Industrial & engineering chemistry research, Vol. 49 N° 22 (Novembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 22 (Novembre 2010) . - pp. 11582-11586 Titre : Reduction of gold ions to gold particles by reusable soluble poly (tyramine) polymerized by horseradish peroxidase Type de document : texte imprimé Auteurs : Hidetaka Kawakita, Auteur ; Yuko Yoshimura, Auteur ; Keisuke Ohto, Auteur Année de publication : 2011 Article en page(s) : pp. 11582-11586 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gold  Ions Résumé : A novel recovery method is proposed for gold ions using poly(tyramine), which is reductive and has easily manipulated solubility. Tyramine, which has phenol and amino groups, was polymerized using horseradish peroxidase. When the HCl concentration in solution was increased, poly(tyramine) solubility decreased, probably due to chloride ion coordination with the poly(tyramine) amino group. Poly(tyramine) was highly soluble at pH <4.0 in the pH region. When the polymer was reacted with gold ion solution in HCl for 48 h, the maximum amount of gold ions obtained was 4.0 mol/kg in a two-step reduction isotherm curve. Filtered reduced gold particles with poly(tyramine) were immersed in 0.1 M HCl solution, resulting in dissolution of the poly(tyramine), and the gold particles were then easily recovered by filtration. Adjusting the pH of the filtered solution to 7.5 allowed recovery of the poly(tyramine) as a precipitate, which could then be reused to reduce further gold ions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100127g [article] Reduction of gold ions to gold particles by reusable soluble poly (tyramine) polymerized by horseradish peroxidase [texte imprimé] / Hidetaka Kawakita, Auteur ; Yuko Yoshimura, Auteur ; Keisuke Ohto, Auteur . - 2011 . - pp. 11582-11586. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 22 (Novembre 2010) . - pp. 11582-11586 Mots-clés : Gold  Ions Résumé : A novel recovery method is proposed for gold ions using poly(tyramine), which is reductive and has easily manipulated solubility. Tyramine, which has phenol and amino groups, was polymerized using horseradish peroxidase. When the HCl concentration in solution was increased, poly(tyramine) solubility decreased, probably due to chloride ion coordination with the poly(tyramine) amino group. Poly(tyramine) was highly soluble at pH <4.0 in the pH region. When the polymer was reacted with gold ion solution in HCl for 48 h, the maximum amount of gold ions obtained was 4.0 mol/kg in a two-step reduction isotherm curve. Filtered reduced gold particles with poly(tyramine) were immersed in 0.1 M HCl solution, resulting in dissolution of the poly(tyramine), and the gold particles were then easily recovered by filtration. Adjusting the pH of the filtered solution to 7.5 allowed recovery of the poly(tyramine) as a precipitate, which could then be reused to reduce further gold ions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100127g